Lids or closures, in a variety of forms, are commonly removably associated with container mouths for allowing selective access to the interior of the container for the introduction or removal of container contents. The closures will normally seal the containers when mounted with the degree of seal depending upon the container contents and the particular construction of the closure.
Conventional closures assume a wide variety of shapes, for example caps, plugs, hinged flaps, and the like. Similarly, a wide variety of means is provided for securing the closure, including mating threads, frictionally engaging surfaces, detents, and the like.
The securing means of each closure is normally a function of the specific type of closure and the desired relationship thereof to the container. For example, the container may be specifically configured whereby the opening is surrounded by a peripheral wall either internally or externally threaded. Such a mouth may comprise the entire upper end of a container or a pouring neck projecting from the closed end of a container. In each case, the closure will include mating threads, either internally or externally in accord with the threaded container mouth. Such closures must, of necessity, include appreciable externally accessible portions to allow for a manual gripping and rotational manipulation of the closure. It will also be appreciated that the container itself need be specifically formed with threads or the like.
Other forms of closures, for example snap-on lids, similarly require the provision of specific means on the container for retention of the lid, as well as means on the lid enabling a positive manual grasping thereof.
One form of closure which can frequently be accommodated in a container opening or mouth without elaborate container modification is a simple plug which is merely frictionally received within the opening. However, provision must also be provided for removal of the plug, either by retaining a specific portion of the plug exposed for manual grasping, or utilizing a specific extraction tool, such as for example a corkscrew for a wine bottle cork.
Another form of closure, normally found on small pill boxes, dispensers, and the like, utilizes a lid which when depressed will pivot about a fulcrum point or points defined on the container itself, the container normally being specifically configured, for example recessed, to accommodate pivotal movement of the lid. A related form of closure utilizes a depending skirt which completely encircles the container wall about the mouth and includes means thereon for engaging a portion of the container wall for a pivotal cooperation therewith. Note for example the following two patents:
______________________________________ 2,327,406 Dukehart, Jr. August 24, 1943 2,351,783 Punte June 20, 1944 ______________________________________
In each of the described instances, the basic shape of the lid is generally dictated by the nature of the sealing and/or opening relationship to the container. For example pivoting lids normally require depending external skirts, screw or plug type closures necessitate provision for manual grasping, lids with limited access require special opening procedures or means.